[SECURITY PATCH 030/117] kern/partition: Check for NULL before dereferencing input string

[Daniel Kiper]

From: Darren Kenny <darren.kenny@oracle.com>

There is the possibility that the value of str comes from an external
source and continuing to use it before ever checking its validity is
wrong. So, needs fixing.

Additionally, drop unneeded part initialization.

Fixes: CID 292444

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/kern/partition.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/grub-core/kern/partition.c b/grub-core/kern/partition.c
index 2c401b866..3068c4dca 100644
--- a/grub-core/kern/partition.c
+++ b/grub-core/kern/partition.c
@@ -109,11 +109,14 @@ grub_partition_map_probe (const grub_partition_map_t 
partmap,
 grub_partition_t
 grub_partition_probe (struct grub_disk *disk, const char *str)
 {
-  grub_partition_t part = 0;
+  grub_partition_t part;
   grub_partition_t curpart = 0;
   grub_partition_t tail;
   const char *ptr;
 
+  if (str == NULL)
+    return 0;
+
   part = tail = disk->partition;
 
   for (ptr = str; *ptr;)
-- 
2.11.0